


Unlasting

by HikariNoHimeWriter



Category: Dr. STONE (Anime), Dr. STONE (Manga)
Genre: Alternate Universe - Canon Divergence, Bottom Shishiou Tsukasa, Dom/sub Undertones, Enough pining to plant a forest, Feminization, Idiots in Love, Lingerie, M/M, Mild Angst, Plot What Plot/Porn Without Plot, Post-Treasure Island, Restraints, There's a one year gap between Treasure Island and America, Top Ishigami Senkuu, feelings denial
Language: English
Status: Completed
Published: 2020-12-28
Updated: 2020-12-28
Packaged: 2021-03-10 19:48:56
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,096
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28392666
Author URL: https://archiveofourown.org/users/HikariNoHimeWriter/pseuds/HikariNoHimeWriter
Summary: And even if this unlasting happiness is all he can have, Tsukasa’s satisfied. For now, it’s enough.
Relationships: Ishigami Senkuu/Shishiou Tsukasa
Comments: 1
Kudos: 11





	Unlasting

**Author's Note:**

  * For [GoBeyondProblematic](https://archiveofourown.org/users/GoBeyondProblematic/gifts).



> A special thanks for my dearest Mic. Thanks for enabling me to write this stupidly delicious story. Hope you enjoy it ♥  
> This piece was heavily inspired by the song Unlasting by LISA.

Unlasting

Life in the stone world is an interesting experience. Grief for their long-lost past and hope for their future define who they are. Ideals and beliefs shape their world, but it’s their actions that make it real. Dreams can become true, for everything is theirs to create and conquer. They’re free to live and love, desire and take. It doesn’t matter who you are nor who you’re with, not when everyone already lost too much to care about those simple things.

Tsukasa felt powerful in this new world. This feeling still chases him over three years after his first revival. He’s not the Strongest High School Primate anymore. He has everything he fought so hard for—the sister he wanted to protect, the friend who showed him what kindness is, a better future to look up for. There’s no need to hide anymore. He can be his true self; he can love whoever he wants.

He is free.

But freedom often comes with the weight of grief and deep-rooted pain. Tsukasa’s aware that Senku doesn’t resent him. The very fact that Tsukasa’s alive and breathing is a proof of it. He didn’t ruin everything, not yet. There’s hope for them. Maybe there’ll be a day when he can finally let go of the last barrier between him and Senku.

One day. Now his chest is heavy with guilt. For everything he did, for every problem he caused, for every mistake Senku looked over to save him. It’s hard to breathe, and only gets harder with each passing day they spend together in the Ishigami Village.

Tsukasa needs to do something to quench this pain. He needs Senku. For redemption, forgiveness, call it whatever you want—as long as he can prove himself worthy of Senku’s efforts, there’ll be nothing he’s unwilling to give him.

It’s easy to leave the priestess’ small island and get away from all festivities. They’ll leave for America soon, and the village insisted on hosting a party for them. If it had been any other time, Tsukasa would have appreciated the sentiment and the joy that filled their day. The songs and crudely made instruments only serve to increase his building headache and the small talks make he feel suffocated.

He can feel the weight of someone’s gaze on his back. Tsukasa swallows past the slow, but steadily building anxiety. He knows exactly who it is, and the knowledge sets Tsukasa’s heart on fire. _He_ knows what he needs. _He_ will come soon fulfill his selfish desires.

Tsukasa presses his lips into a thin line. He walks past Chrome’s cabin and follows the soothing, rhythmic sounds of the river. The moon is full tonight, making it easier to find his way to the secluded cavern just by the riverside. Tsukasa lights up the torches lined up on the walls. The crackling flames both calms and excites him. It breaks the silence and leaves room for intrusive thoughts; it warms his heart and body, in more ways than just one.

He stares the round stone in the middle of the cave. It’s covered in straws and bedsheets, making it comfortable enough to lie for hours without lingering pains—at least none that comes from the bed itself. Tsukasa knows this all too well, having been to this place far too many times during the few months since his revival.

He reaches for the lace keeping his cape together and undoes it slowly. Tsukasa inhales sharply as the only physical reminder of the day he and Senku met falls to his feet. He steps out of his pants next. A shiver runs down his spine as a cold breeze hits his skin. He feels lighter, free, and _oh_ so painfully exposed to the world to see. Vulnerable. Defenseless against the stares and desires harbored towards him.

Tsukasa kneels by the bedside and reaches for what’s underneath the makeshift mattress. He closes his hand around a cold, cold chain. Both ends meet a handcuff, the key nowhere to be seen—it lies in the safest of places, right under a bloody equation Tsukasa will never forget. He discards it for now, searching for his true objective. A shuddering sigh escapes Tsukasa’s lips when he finally finds it.

The soft fabric still feels foreign to him. He glances down at the delicate shapes and details Yuzuriha so hard worked on. The size is just right to fit Tsukasa’s body, a gift he’s unsure if he should or not be grateful for. The idea of Yuzuriha _knowing_ about this arrangement sets him on edge with anxiety. But no matter how much he fights it, he can’t deny himself the rush of pleasure he feels as the bra covers his hardening nipple and the lacy pants hides his precious secret place.

Tsukasa is more than an unmatched fighter. Right now, in the eternity of this moment, he feels _beautiful_. And the one person who made it possible, real, is the only one Tsukasa will ever allow to touch and take and conquer him.

_Senku_ , he calls in his mind, _when are you coming to me?_

He picks the chains again, then swallows. Tsukasa hooks them on the wall with practiced ease. The metal feels cold against his wrists. Tsukasa lies on the bed, his feet pointed towards the entranced and chains keeping his arms high above his head. He doesn’t mind it. He could tear everything apart with the slightest pull if he so wished. He’s not a prisoner, not to this place, not to Senku and not to the guilt filling his chest. No, Tsukasa’s master is something deeper, a raw, incomparable feeling he refuses to acknowledge. It’ll do nothing good for him, for them.

Tsukasa’s unsure how long passed before he hears the sound of footsteps. They’re light and muffled, unlike the village’s traditional sandals. He knows he can’t be Gen, for Tsukasa can never hear the mentalist’s steps. His breath hitches and quickens anew. Tsukasa licks his lip, tries to regain control over his heartbeats—and it only takes a glimpse of red eyes for Tsukasa to fail miserably.

Senku stands there, unmoving, but Tsukasa knows his mind is running miles a second. He can feel Senku’s gaze running all over his body, a ghost caress that makes his lips tremble. For once the scientist’s attention are solely focused on him. There’s no one here to take Senku away, to distract him with mundane affairs Tsukasa had no part in.

In this moment Senku belongs to him as much as Tsukasa belongs to him. Tsukasa wouldn’t change this sensation for the world.

As if breaking a spell, Senku chuckles. The sound of it echoes in the small cavern, deep and promising. Tsukasa’s nails dig into his palms. Senku approaches him with deliberately slow steps. He joins his hands behind his back, leans over the edge of the bed. Tsukasa can feel his scent now—wine and smoke, with a hint of something muskier underneath. He wants Senku to come closer, touch him, cover him with his scent.

“Look what a beautiful doll we have here.” Senku’s voice sends a shiver down Tsukasa’s spine. A cold finger touches Tsukasa’s shoulder, traces the outlines of the bra down his chest. Tsukasa grits his teeth at the tease. “All ready for me. Lovely.” His fingers brush a strand of hair out of Tsukasa’s chest. Nothing will stand between Senku and the sight before him. “Did you prepare yourself too?”

Tsukasa opens his mouth, then closes it again. He shakes his head in lieu of an answer, fearing his voice would fail him. Senku smiles and those feather-light touches are gone. Tsukasa waits for his next move. Will Senku touch him? Take him? Tease him until Tsukasa’s begging? Or will he go for a completely different route? Command and reward? Punishments?

His head spins with all the possibilities. He wants all of it, every and anything Senku’s willing to give him. He’s far too gone to stop now. Tsukasa’s cock strains against his panties, leaking and almost painfully hard. He knows Senku can see it, knows the scientist takes pleasure in the sight. Senku’s powerful, more than anyone imagines, and Tsukasa now feels the sheer weight of his lover’s influence.

“Such a dirty little thing you are,” Senku all but coos at him. He takes a seat at the far end of the bed. Tsukasa unconsciously spreads his legs a little more, exposing more of him and giving Senku room to crawl over to him. Senku holds his foot instead. Tsukasa’s hyper aware of how small Senku’s hands are, having to use both hands to keep his leg in place. He presses his lips against Tsukasa’s ankle, gentle and almost reverent. “Did you want me this much? Couldn’t even wait for me to dress up?”

Senku’s fingers all but dance across Tsukasa’s skin, gentle caresses and squeezes that take his breath away. Senku tilts his head, watching his reactions with fixed interest. Tsukasa can only wonder what’s going on in his mind. Does he really see beauty in Tsukasa or is it all just a part of a new, exciting experiment? Tsukasa has no answer for that question. He can’t bring himself to care about it anymore either, all thoughts knocked out of him when slender fingers brush against his inner thighs.

Tsukasa moans, open and unrestrained. His breath comes out in heavy pants and a thin layer of sweat covers his body, reflecting the golden firelight. To think he is already in this state and Senku barely started with him... Tsukasa would’ve died of shame if he wasn’t dying of desire now. He licks his lips. “S-Senku...” His voice sounds hoarse to his own ears. The metal around his wrists is the only thing grounding him to reality. “Please...”

“What is it?” Senku's red eyes are darker now, a color closer to that of blood instead of rubies. Tsukasa’s breath hitches. “What do you want?”

_Kiss me_ , the words flash in his mind right away. Tsukasa’s gaze falls to Senku’s lips. They’re thin and red and chapped at the corners. There’s a little cut on his lower lip. Does he not know not to bite himself so hard? Tsukasa wants to feel them over his own, taste the village’s wine from Senku. Tsukasa wants him, through and through.

“Use me,” he says instead. The safer answer, the one that won’t ruin everything they built together. “Make me scream.”

Senku sucks in a breath. His eyebrows furrow and he bites his lip again. He looks almost _pained_ , but that, too, disappears as he breathes out, “Word?”

Tsukasa’s safe word, the only thing that will make Senku stop. He’s not a prisoner, nor a slave. His desires and wishes matter for Senku. This in itself is already more than Tsukasa could ask for. He sighs. “Last.”

He shivers. This word is both a curse and the realization of his hopes. _For the last time, no more_ , it says, merciless and demanding. _Please, let this moment last forever_ , an unfulfilled wish, a request Tsukasa has no right to make.

Senku nods. He leans back, taking his time to remove his clothes. His belt meets the ground first, the tools inside clinking in the silence. Senku kicks his shoes off, fingers working his robe off. Tsukasa’s heart beats faster with each new inch of exposed skin. Senku’s small and arguably weak, but there’s no denying the effort he puts into his work over the past years. Tsukasa’s gaze follows each curve and dip and lean muscles. Senku’s body is _perfect_ in every form and shape of the word. Tsukasa’s fingers itch to touch him, trace every small scar and kiss them goodbye, show Senku just how much Tsukasa truly wants him and, maybe, _more_ than that.

“Red really is your color,” Senku comments idly. Tsukasa blinks at him, confused. It takes a moment to remember that his lingerie is red—red, like Senku’s eyes. The scientist smirks. His fingers slow, but steadily remove the sash covering his arms. “Maybe I’ll ask Yuzuriha for a dress next time. Maybe Minami will have a make-up too. What do you think, Tsukasa? Will you be the prettiest lady for me?”

Tsukasa bites his lip. It does nothing to hide the shudder that runs down his body, nor the way his hips swayed in place, silently begging for something to fill him. Senku’s hands _burn_ him when his hands return to his body. Tsukasa can _feel_ his smile when Senku presses his lips to his stomach. A shuddering sigh escapes him as Senku’s warm tongue traces Tsukasa’s abdomen—all muscles he once hated, all muscles he learned to love.

Senku’s fingers hold onto Tsukasa’s hips, pressing them onto the bed. There’s little strength to it, not nearly enough to keep Tsukasa in place. But it’s _Senku_ , and there’s not a single atom of Tsukasa’s body that doesn’t surrender to this man’s wishes.

Senku’s lips form a trail down his torso again. A shiver runs down Tsukasa’s spine when Senku’s hot breath hits his covered cock. Senku places a fleeting kiss to the leaking head through the fabric before pulling his panties to the side. Tsukasa barely has time to sigh in relief—finally, _finally_ free—before something wet and warm wraps his cock.

He throws his head back, mouth open as breathless moans escape him. Senku bobs his head up and down, taking a little more of Tsukasa inside each time. He can feel Senku moaning around him, the vibrations adding to the pleasure of being all but crushed by the man’s throat. Tsukasa loves this, loves how well Senku takes him, the way he makes his pace painfully slow every time he thinks Tsukasa’s about to cum. He’s addicted to this delightful torture, addicted to Senku. He wants more, _oh_ , so much more—but can he ask for it after everything he did?

Tsukasa gasps when one of Senku’s fingers start probing at his entrance. It’s wet, but not nearly enough to compare with the lube Senku made for them. Tsukasa shudders. Tsukasa, who always takes pleasure in the roughest nights. Just the idea of being fucked raw by Senku makes him wriggle in anticipation. He’s a masochist through and through, and Senku knows it all too well.

He forces his body to relax. Senku lets go of his cock with an obscene _pop_. He smiles at Tsukasa, sweat dripping his forehead with the effort. “That’s it,” he praises, voice lower than ever. “Just relax. My good boy.”

Tsukasa blinks. Why does Senku look so blurry now? He’s right here and _oh_ , he thinks as something wet rolls down his cheek, _it’s me. I am crying_. Tsukasa averts his gaze from Senku, trying to hide that small, lonely tear that had no reason to be.

A second finger invades him, scissoring him open. Tsukasa’s once again in awe at how small Senku’s hands are compared to his own, yet those small hands are the ones bringing him a pleasure Tsukasa could never achieve by himself. So powerful, Senku is. There’s nothing he can’t conquer with his hands and effort. Tsukasa wonders if Senku is even aware of it, if that’s what drives him to give Tsukasa a heaven he does not deserve.

Senku removes his fingers when he deems Tsukasa ready. Tsukasa holds his breath as the scientist lines his cock with his gaping hole. It only takes a moment, a glance at Tsukasa’s expression, a silent confirmation, before he pushes inside.

It hurts. It always does. A deep ache followed by the sweet, sweet burning of skin against skin. He can’t help the slight frustration at the realization that it doesn’t hurt as much as he thought—unlike his fingers, Senku’s cock is covered with lube, the empty vial discarded at the end of the bed. Tsukasa still wants it. He wants more of this feeling; he wants to feel everything Senku has to give him.

“ _Fuck_ ,” Senku curses through gritted teeth. His fingers dig into Tsukasa’s hips and his face is contorted into a frown. And he looks so devastatingly beautiful under the golden light of the flames around them. Tsukasa wants to reach for him, pull him closer, kiss him, but the chains remind him he can’t.

Senku notices. His eyes soften as he looks at Tsukasa and he leans closer to him. Senku’s lips ghost over his collarbone, his teeth nibble and dig into Tsukasa’s shoulders and neck. He moves his hips, takes almost everything out before thrusting back inside. Slow, careful, like a true lover would. Tsukasa’s breath quickens and hitches, his voice comes out in a string of broken moans and hiccups. Senku runs his tongue on the shell of Tsukasa’s ears, whispers dirty sweet nothings that make Tsukasa’s eyes roll in pleasure.

He wraps his legs around Senku’s waist, forcing him to go deeper inside him. Senku chuckles, breathless and hoarse, “Needy, are you now?” Tsukasa cries out when Senku rolls his hips just _right_. One of the scientist’s hands wrap around Tsukasa’s cock, slow, but steadily jerking him to completion. “It’s okay. You can cum now.”

The words force a shuddering moan from Tsukasa, but it’s Senku’s lips that push him over the edge. Tsukasa moans into the kiss. Senku tastes of sweet wine and salt and something else Tsukasa can’t quite pinpoint now. Spasms flow through his body as he cums on Senku’s fingers. Senku follows him almost immediately, flooding Tsukasa’s insides with his hot seed.

Tsukasa closes his eyes. He focuses on the sounds of their ragged breaths, on the feeling of Senku’s weight over him. It’s warm. It’s perfect. And, _oh_ , so much more precious than anything they ever had before. Maybe, Tsukasa muses, because it’ll all disappear the next time he opens his eyes. They’ll go back to their awkward friendship and push back this desire for the sake of their next adventure.

And even if this unlasting happiness is all he can have, Tsukasa’s satisfied. For now, it’s enough.

In the middle of his peaceful sleep, Tsukasa won’t see how Senku gently unties his hands, massaging and kissing the sore spots. He’ll never know of the love simmering in his red eyes as he covers Tsukasa’s body with a light sheet. The moonlight filtering into the cavern is the only witness of Senku’s silent devotion. It’s okay, even if Tsukasa never knows. As long as they’re together, Senku can find the strength to move on. It’s all he needs...

_For now_.

**Author's Note:**

> Link to the art on my Deviantart  
> Check my [Twitter!](https://twitter.com/HikariNoHimeW)


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